Professor Kenichi Soga delivered a keynote lecture entitled ” Mechanics of Fluid-Grain Interaction from Micro to Macro” at the IS Atlanta 2018 conference which was held in Atlanta from 10-13th September, 2018. IS-Atlanta 2018 is the fourth quadrennial international symposium organized under the auspices of Technical Committee 105 (Geo-Mechanics from Micro to Macro) of the International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE).